Dale hikes up a mountain trail at 2 mph. Because Dale hikes at 4 mph downhill, the trip down the mountain takes 30 minutes less time than the trip up, even though the downward trail is 3 miles longer. How many mile did Dale hike in all?

13 miles

Step-by-step explanation:

He hikes 4 mph downhill and it takes 30 minutes or 0.5 hours lesser than the trip uphill at 2 mph.

Thus, if the distance upward is x and we are told the distance downhill is 3 miles longer.

Then, since time = distance/speed, we have;

((x + 3)/4) + 0.5 = x/2

Multiply through by 4 to get;

x + 3 + (0.5 × 4) = 2x

x + 5 = 2x

2x - x = 5

x = 5 miles

Now, it means distance uphill = 5 miles and distance downhill = 5 + 3 = 8 miles

Thus, total distance covered = 8 + 5 = 13 miles